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Perennials with Interesting Flowers

This article was published originally on 6/12/1998

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by Amanda Lorimar, Department of Horticulture

Home gardeners can choose from many species and varieties of perennials. Perennials differ in growth habit, size, leaf morphology, and other characteristics. Sometimes what sets one perennial apart is its interesting flower. Below is a list of perennials with unusual flowers.

For interesting late spring bloom, try Columbine (Aquilegia hybrids). The foliage is blue-green, softly pubescent, and dissected. The flower is composed of five petals and five sepals. The petals have backward projecting spurs which contain a honey-like substance. The sepals are shorter than the petals and may be the same color or a contrasting color. Colors for the sepals and petals include red, pink, yellow, blue, white, and purple. This plant grows to 1 to 3 feet tall by 1 foot wide. It prefers full sun to partial shade and well-drained soil. Columbine plants can be used in the perennial garden and to attract hummingbirds. Columbine has a unique seed dispersal mechanism that propels the seeds away from the mother plant. This mechanism allows columbine to make its way around the garden as a "traveler". Because the flowering season ends early, another perennial or annual should be planted in front of columbine to cover up the fading foliage and flowers.

Dutchman's Pipe (Aristolochia durior) is a deciduous vine with uniquely-shaped flowers. The vine can reach 20 to 30 feet in height. The heart-shaped leaves are large, glossy, and dark green. The flowers are the vine's main attraction. In late spring to early summer, pipe-shaped flowers appear. They are yellow-green to brownish-purple in color. This vine tolerates a wide variety of soils in sun or shade and provides a quick cover.

For moist soils, Pink Turtlehead (Chelone lyonii) is an excellent selection. Turtlehead has dark green foliage and a dense, upright growth habit. In late summer to early fall, hooded pink flowers appear at the end of the stems. Pink turtlehead gets its name from the resemblance of the flowers to the head of a turtle with its mouth open. Generally, the plant is 3 feet tall and 2 feet wide. Partial shade to full sun and a consistently moist to wet, organic soil are ideal conditions for growth. This plant usually does not require staking unless the area is too shady. Turtlehead does well along a stream or pond, in a perennial bed, or in a wild garden.

Old-fashioned Bleeding Heart (Dicentra spectabilis) has blue-green, dissected foliage. Flowers hang down from arching stems in late spring to early summer. The outer petals are rose-red with reflexed tips. The inner petals are white. Bleeding heart gets its name from the flowers that resemble pink broken hearts. This plant grows to 2 to 3 feet with a graceful arching effect and a rounded growth habit. Bleeding heart performs best in well-drained, moist soils in partial to heavy shade. In the heat of summer, the plants often go dormant and die back to the ground. Because of this dormancy, another perennial or annual should be placed nearby to cover the dying foliage. This plant can be used in the shade garden and as a cut flower.

Gas Plant (Dictamnus albus) gets its name from the plants' ability to produce a volatile gas. On a calm summer evening, the gas can reportedly be ignited with a match. A brief blue flame is created without damaging the flowers. The pinnate, 3-inch-long leaves give off a lemon fragrance when crushed. The large, showy, terminal racemes appear in late spring to early summer. Colors range from white to pink to rose-violet. This plant will grow to a height of 2 to 3 feet and an equal width. Gas plant prefers a sunny location with moderately fertile soil. Because the gas plant grows very slowly and does not transplant well, gardeners should carefully select its planting site and exercise patience. Do not disturb plants if at all possible. Uses for this perennial include specimen plantings and attractive seed pods. The foliage and flowers may cause a severe dermatitis on some people.

Sea Holly (Eryngium amethystinum) has rigid, deeply cut, spiny, silvery foliage. The blue flowers appear in heads that are 1/2-inch to 3/4-inch in diameter. Long, spear-like bracts surround the heads. Blooms appear in midsummer. Sea holly prefers full sun and sandy, dry areas. This perennial is tolerant of dry, sunny conditions and infertile soils. It can be used as a single specimen or in groups of three. Sea holly can also be used as a dried flower.

To add bright colors to the perennial garden, incorporate specimen plantings of Red-Hot Poker (Kniphofia hybrids). The foliage is linear, or sword-shaped, and gray-green with rough edges. Tubular flowers appear massed in the top 6 to 10 inches of the flower scape in the summer. Flower colors include red, yellow, coral/orange, and combinations. The plant has a mature height of 2 to 4 feet and a width of 3 feet. Red-hot poker prefers a site with full sun and well-drained soil. Avoid planting this perennial in heavy, wet soils. Because of its uniqueness, plant red-hot poker either as a single specimen or in groups of no more than three together. The flowers can be used as cut flowers. Mulch heavily in winter.

Gooseneck Loosestrife (Lysimachia clethroides) has pubescent foliage that changes from dark green in the spring to bronzy-yellow in the fall. White flowers are produced on a 6-to 12-inch curving flower stalk that resembles the neck of a goose. The plants are 2 to 3 feet tall with a spread of 3 feet or greater. Because loosestrife is aggressive, it may be necessary to remove portions of the plant each year to control growth. Full sun to partial shade and moist, well-drained soil are requirements for optimum growth. This plant is best in an informal bed or naturalized area. Plant gooseneck loosestrife at least 3 feet from the nearest plant to minimize problems. This plant is heat tolerant. The blooms can be used for cut flowers.

Beebalm (Monarda didyma) has foliage that is serrate and aromatic and stems that are square. Two-to three-inch, tubular flowers occur in dense heads from late spring to summer. Deadheading promotes bloom. This plant grows to a height of 2 to 4 feet with a spread of 3 feet. Beebalm prefers full sun and good soil moisture. Although it is heat tolerant, beebalm is not drought tolerant. This perennial is also susceptible to powdery mildew so take care to keep the foliage dry and provide adequate air circulation. If beebalm is to be used in the perennial bed, divide plants every 2 to 3 years as it spreads rapidly. Beebalm can be used in naturalized areas and to attract bees, hummingbirds, and butterflies.

For late summer bloom, try Obedient Plant (Physostegia virginiana). The spear-like, serrated leaves are green in the growing season and sometimes crimson or red in the fall. The stems are square. The flowers appear in spikes spaced in four vertical rows. Flower colors include rose, purple, and white. The plant grows to a height of 2 to 4 feet and a width of 3 feet. The ideal site includes sun to partial shade and moist, acidic soils. Because of its height, staking may be required. The obedient plant spreads vigorously. It needs to be contained by frequent roguing, or removal of unwanted plants. The obedient plant requires little or no fertilizer. Heavy fertilization promotes rampant growth and increases the plant's invasive tendencies. Obedient plant is heat tolerant. The bloom may be used as a cut flower. Obedient plant gets its name from the ability of individual flowers to be twisted on the stem and then remain as arranged.

Balloon Flower (Platycodon grandiflorus) has serrated, dark green leaves that are 1 to 3 inches long with short petioles. The saucer-shaped flowers appear in summer in lavender, blue, pink, and white. Several double-flowering varieties are available. The plant has 2-to 3-foot erect growth. Balloon flower prefers sun to part shade and well-drained, slightly acid soil. Because this plant is slow to emerge, care must be taken not to injure the crown when cultivating the soil in early spring. The plant does well as a cut flower, in rock gardens, and in perennial beds.

For the perennial border, try Pincushion Flower (Scabiosa caucasica). The basal leaves are linear, but the leaves on the stem are divided. For three to four weeks in the summer, light blue or pink, flattened flower heads appear on long stems. Cultivars such as 'Butterfly Blue' and 'Pink Mist' can bloom for 2 months. The flower head consists of an outer ring of flattened petals and a tufted, cushion-like center. The shape of the flower gives pincushion flower its name. Plants are 1 1/2 to 2 feet tall and 1 1/2 feet wide with a rounded growth habit. Full sun and well-drained, fertile soil are necessary for optimum growth. The pH should be near neutral. To promote flowering, spent blooms should be removed. For the best effect, plant this perennial in the perennial bed in groups of 3 or more. In addition, the blooms can be used as cut flowers. Mulch plants in the fall to prevent them from being heaved out of the ground by repeated freezing and thawing of the soil during the winter months.

Another perennial with late summer to early fall bloom is Toad Lily (Tricyrtis hirta). The foliage is 3 to 4 inches long, pubescent, and parallel-veined. The flower is pale lilac to white with dark purple spots. Plants possess an upright growth habit, are 2 to 3 feet tall, and are 2 feet wide. Toad lily prefers part shade and moist, well-drained soils high in organic matter. This plant is excellent for the lightly shaded perennial bed. Because the toad lily flower is not showy from a distance, the plants should be placed where the flowers can be closely observed.

This article originally appeared in the June 12, 1998 issue, pp. 74-76.